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Kinetics and thermodynamics of 1-anilino-8-naphthalene sulfonate interactions with Urinary Trypsin Inhibitor
Zhenyu Zuo1, Handong Fan, Jianjun Guo
1College of Chemical Engineering and Technology, Wuhan University of Science and Technology, Wuhan, 430081, China. zuozhenyu@wust.edu.cn
Abstract:
The interactions between Urinary Trypsin Inhibitor (UTI) and 1-anilino-8-naphthalene sulfonate (ANS) were investigated by fluorescence spectra, isothermal titration calorimetry and molecular modeling. The results revealed the presence of four specific binding sites for ANS on UTI, with interactions driven mainly by electrostatic forces. The four specific binding sites indicated the involvement of four hydrophobic patches on UTI. Experimental data also confirmed the presence of a further five nonspecific binding sites that interacted mainly by the formation of salt bridges between the sulfonates of ANS and positive residues on the surface of UTI.
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